Gents, I have read about possible galling/wear issues when using a titanium retainer in street applications. Which is of course what I intend to do ( )... so, what do you think about running a spring steel Rockwell C44 .015 shim underneath the retainer? It's a Manley 23622 retainer, 6AL-4V alloy. On a beehive. Already have the retainers, so not too keen on buying something else (tool steel or Ti-17) and want the weight savings (over regular steel).

I thought it would be best to machine it (the shim) to a reasonably snug fit on the ID and to chamfer/radius the upper side of the shim's ID as well. Don't want to create problems while trying to prevent one.

Good idea, bad idea, indifferent?

 

Bad idea. We have tons of street engines running Ti retainers. Bee hive no issues with Chrome moly, they are very light. If you want extrem weight loss and extreme durability go with tool steel.

 

I don't see too much galling or wear, except when the spring and retainer fitment is poor.

 

Why ?

 

With good spring prep (Important) you should have no issues with galling a Ti retainer.

 

Most retainers have a lip to locate the spring. You cover that lip up the retainer is not properly locating the spring. Like others have said, you can slightly ID chamfer the spring to remove any edges.

 

Well, yes, I was planning on not covering that up . . . .640 OD step on the retainer would require a minimum .640 ID on any shim, plus whatever is needed to accommodate the radius on the underside of the shim's step.

Was planning on that... I see that Crane or Crower sell a wildly overpriced tool, looks like 45 degrees, I presume you can just use a 45 degree stone and accomplish the same thing.

Perhaps what I read was internet hysteria or the result of sloppy builds (the chamfering noted above), but since I have read that in general titanium doesn't like rubbing up against stuff, and since it seems that springs rotate while in operation, the idea of the spring rotating against the Ti retainer would not be a good thing, even though the retainer is hardened to some specific depth, which it hopefully does not wear beyond (assuming the retainer does not rotate in concert with the spring).

Unless a Ti retainer is supposed to be an interference fit with the spring, in which case they would rotate in concert. Generally speaking I am under the impression that an interference fit -- retainer step to spring ID -- is not the situation for the garden variety spring and (steel) retainer.

I also thought a shim might help with the fatigue issue (if that also really exists) by spreading the load from a direct point contact with the mostly or partially rounded spring (where it meets the retainer). Keeping in mind that I'd be looking for, say, 40K miles out of this stock-cammed LS7 street setup as long as the springs hold spec tension. If this is unreasonable mileage target for a Ti retainer, please yell. Loudly

So, to sum up my rambling thoughts, the goal of the shim is:

1. insurance against any galling/wear. If overkill, then the cost is insignificant as long as the shim doesn't cause problems.

2. load distribution to minimize fatigue. If not needed, then again the cost is insignificant as long as the shim doesn't cause problems.

I see that #1 is probably not an issue with a proper installation.

Is there any validity to #2?

 

#2 is not an issue. Yes the spring are round or arc wire but the ends are gorund flat so these is even load distribution. In a proper setup these is not enough load, edges or rotation that I would worry about Ti. Only customers I sway away from Ti are circle track racers running dampered springs. the damper has a sharp edge that will gull the retainer. Otherwise I never really worry about. if you are concerened enough i would just go with tool steel.

 

I've torn down LS engines that I built over ten years ago with Ti retainers on 918 springs and observed no problems whatsoever. I think you might be overthinking

 

You are probably right; I tend to do that. I'll get the lobotomy scheduled ASAP

Learning as I go, so thanks for the input guys!